Method of forming hollow plastic articles



Feb. 16, 1960.

Original Filed March 3, 1954 o. B. SHERMAN Re. 24,784

METHOD OF FORMING HOLLOW PLASTIC ARTICLES ,2 .3. jig.

fi d-[- 5 Sheets-Sheet l ZZ L I a ///////{/2 y} INVENTOR. OKWLLEB.Jimmie Feb. 16, 1960 o. B. SHERMAN Re. 24,784

METHOD OF FORMING HOLLOW PLASTIC ARTICLES Original Filed March 5, 1954 5Sheets-Sheet 2 INVENTOR. ORYJLLEflJHERMA/V BY /d JM Feb. 16,- 1960 o. B.SHERMAN Re. 24,7 4

METHOD OF FORMING HOLLOW PLASTIC ARTICLES 5 Sheets-Sheet 3 OriginalFiled March 3, 1954 V AV A 2/ II i 1 li r! IA 3g INVENTOR.OKVJLLEaJHERM/M' BY ATTORNEY 5 Feb. 16, 1960 o. B. SHERMAN Re. 24,784

METHOD OF FORMING HOLLOW PLASTIC ARTICLES Original Filed March 5, 1954 5Sheets-Sheet 4 3 /4 j g////////As@\\\\ INVENTOR. ORVILLEB. 5125mm BY 6J4f/ flTTOKNEYS Feb. 16, 1960 o. B. SHERMAN METHOD OF FORMING HOLLOWPLASTIC ARTICLES Original Filed March a, 1954 5 Sheets-Sheet 5 IN V ENTOR. OJEYILLE B. SHEKMA N BY J 6M ATTORNEYS Re. 24,784 Reissued Feb. 16,1960 METHOD OF FORMING HOLLOW PLASTIC ARTICLES Orville B. Sherman, WestOrange, NJ assignor to Owenslllinois Glass Company, a corporation ofOhio Original No. 2,804,654, dated September 3, 1957, Serial No.413,855, March 3, 1954. Application for reissue September 12, 1958,Serial No. 761,281

12 Claims. (CI. 18-55) Matter enclosed in heavy brackets appears in theoriginal patent but forms no part of this reissue specification; matterprinted in italics indicates the additions made by reissue.

This invention relates to a method of forming hollow plastic articlesand particularly to a method of forming articles having a neck finishand made of organic plastic material.

According to one method of forming hollow plastic articles, a blankcomprising a neck finish with an integral length of tubing is formed andsubsequently expanded to the confines of a mold by applying fiuid underpressure.

It is an object of this invention to provide a novel method of formingsuch a blank, comprising a neck finish and integral length of tubing,wherein the dimensions of the neck finish are accurately and uniformlycontrolled.

It is a further object of this invention to provide such a methodwherein such a blank may be formed rapidly with the elimination of flashand other waste during the forming.

Other objects of the invention will appear hereinafter.

Basically, the invention comprises extruding a measured quantity ofplastic material into a tubular openended cavity through an opening incommunication with a source of plastic under pressure, isolating themeasured quantity of plastic in the tubular cavity from the parent massof plastic, applying a force to the isolated quantity to force a portionthereof to move into a neck mold overlying the end of the cavity,re-establishing communication of the plastic in the cavity with theparent mass, forming a length of tubing integral with the neck finish bymoving the neck mold away from the tubular cavity and simultaneouslysupplying plastic material to the tubular cavity from the parent mass,thereby forcing plastic material out of the cavity and simultaneouslyreplenishing the plastic material in the cavity, isolating the plasticin the cavity from the parent mass, and severing the neck finish withthe integral length of tubing from the plastic material in the cavity.The completion of the severing step leaves the tubular cavity filledwith plastic and in position for application of pressure to forceplastic material into a neck mold and thereby again begin the cycle ofsteps.

Referring to the accompanying drawings:

Figs. 1 through 6 inclusive are sectional elevational views of anapparatus for performing the method, showing the parts in differentpositions corresponding to various steps of the method;

Figs. 7 through 10 and 13, 14 and 15 inclusive are sectional elevationalviews of another apparatus for performing the method, showing the partsin difierent positions corresponding to the various steps in the method;

Fig. 11 is a sectional view at the line 11-11 of Fig. 9;

Fig. 12 is a sectional view at the line 1212 on Fig. 7;

Fig. 16 is a part sectional elevational view of an apparatus forperforming the method; and

' Fig. 17 is a part sectional elevational view of the apparatus shown inFig. 16 with the parts in the position obtaining at the completion ofthe injection operation.

As shown in Figs. 1 through 6, an apparatus for performing the methodincludes a body 20 having a vertical opening therethrough and an orificering 21 overlying the vertical opening. A mandrel 22 is positioned inthe opening thereby forming a tubular cavity 23. The tubular cavity 23is in communication with the outlet of a plasticizer and extruder (notshown) through a channel 24.

A sleeve 25 surrounds the mandrel 22 and is reciprocable by means (notshown) from a position above and overlying the channel 24 to a lowerposition whereby the tubular cavity 23 may be brought into and out ofcommunication with the channel 24.

A partible neck mold 26 and a hollow core 27 are mounted above the body20 for axial movement into and out of alignment with the open end of thecavity 23. A partible finishing mold 28 (Figs. 5 and 6) is provided forexpanding the plastic to finish form, as hereinafter described. Thebottom of the mold sections are beveled at 29 and spaced apart as 30 inorder to pinch the plastic material and seal the end thereof.

At the beginning of the operation of the apparatus shown in Figs. 1through 6, a quantity of plastic material sufficient to fill the tubularcavity is introduced from the source of plastic through the channel 24to the cavity. The mass of plastic material in the tubular cavity isisolated from the parent mass of plastic material by movement of thesleeve 25 upwardly across the channel 24. The apparatus is then inposition for the beginning of the cycle and the neck mold 26 is broughtinto contact with the body 20, the core 27 contacting the mandrel 22(Fig. 1).

The sleeve 25 is then moved upwardly under controlled pressure asufficient distance to force a portion of the plastic material in thetubular cavity upwardly in order to fill the neck mold 26 and form thefinish of the article (Fig. 2). The sleeve 25 is then retracteddownwardly to re-establish communication with the plastic material (Fig.3). Simultaneously the neck mold is moved upwardly and axially away fromthe end of the cavity. The pressure of plastic material from the parentmass forces plastic material into the tubular cavity. A portion of theplastic material in the cavity 23 is displaced out of the open end ofthe cavity, thereby forming a length of tubing integral with the neck.As the desired length of tubing is formed, the sleeve is again movedupwardly to cut ofi or resegregate the parent mass from the plasticmaterial in the tubular cavity. A shear blade 31 is then moved acrossthe orifice to sever the length of tubing from the plastic material inthe tubular cavity (Fig. 4).

The sections of the hollow mold 28 may then be closed about the plasticmaterial, thereby pinching the lower end of the tubing. The tubing maythen be expanded to the confines of the mold by applying fiuid underpressure through the hollow core 27 (Figs. 5 and 6).

After the tubing has been severed from the plastic material in thecavity (Fig. 4), the apparatus is again in position for beginning thecycle by bringing a neck mold into contact with the body 20 and formingthe neck finish by moving the sleeve 25 upwardly.

A modification of the method may be performed by retracting the sleeve25 at the beginning of the cycle as shown in Fig. 5a to permit a limitedquantity of plastic to enter the tubular cavity and then moving thesleeve upwardly, simultaneously isolating the quantity of plastic in thetubular cavity and forcing plastic into the neck mold positioned overthe cavity as shown by Figs. 2 and 8. The sleeve is then retracted andthe neck mold moved axially away from the cavity to form a length oftubing integral with the neck, in the same manner as'heretoforedescribed. As the desired length of tubing is formed the sleeveis' againmoved upwardly as in Fig. 4, or rotated as in Fig. to isolate orresegregate the plastic material in. the cavityandthe length of -tubingis severed." The. cycle of "operations, could then againbe started bythe retraction of Zthe sleeve.

Another" apparatus" for" performing the" method. is shown'inFig's.7th1'ough 15, inclusive. Ifr'this apparatusthe"sleeve 25' is provided'with a slot orgroove32 extending longitudinally along the outer"surface of the sleeve to the upper end thereof. In the operation ofthis apparatus the'tubular cavity is initially filled Withplasti'cmaterial as in the form ofthe apparatus .shoWn.. in.

Figs..1 through 6. The sleeve.25f is vin thewposition showndn'Fig. 7'wh'erein'thel plastic .ma-teria'lin .the. tu.-. bula'r cavity isisolated or segregatedffr'dm.communicationwith the parent massandItheQgroove. 32li'isin,.a

position out of "communication with .the..-channel .24... (Fig.

12.). The sleeve. 25' is'th'n' movedfupwardliy; to..force plasticmaterial into. theneck finish (Fig.1 8). to bring the groove 32" intocommunication. with] the channel' 24" thereby permitting plasticmaterialtoflowfrom'the parent mass to the tubular. cavity.(Figs.-.9,q.l1).

Simultaneously with" this action the neck moldis movedaxially away fromthe cavity. thereby. forminga length.

of tubing integral with the. neckfinishby, thefiow of plastic materialoutofthe tubular. cavity. During the forming of the tubing tlie sleeve.is retracted; into its lower position. As the desired length of'tubingisformed, the sleeve is again rotated'toibring. the groove..32.out of register with the channel 2'4isolating, or. resegregating theplastic material in the cavity fromthe parent. mass (Fig. 10).

The neck finish and integral tubingmay thenbe severed' (Fig. 10')" andsealed and expanded, as shown in Figs. 13 and 14, by closing themold'sections and supplying fluid under pressure through the, core...

At the severing of the tube from the materialin the tubular cavity, thevarious. parts are again in. position for application of pressure to themass of plastic in the, tubular cavity to force plastic out ofthetubular cavity and once again begin the cycle. of formingas-hollowplastic container.

Figs. 16 and 17 show an apparatus for making a multlplicity of hollowarticles at the'samew time. For ex.-

ample, as indicated in Figs. 2 and 15, the sleeves 25 and 25'respectively, are shown. as having been moved upwardly to injection moldthe neck portions of the. next succeeding article. The apparatus in Fig.16 ,may be used. to form articles according to the-method shownin 1through 6. The apparatus includes a body 33 having two verticalopenings. therethrough" and an orifice plate 34 also provided with. twoopenings in register with the openings in the body. Mandrels 35, 36 arepositioned in the openings forming cavities 37, 38, respectivel'y'. Thecavities 37, 38" are in. communication with the outlet of a plasticizerand extruder (not shown) through channel 39. Sleeves 40, 41 are mounted.on cross-arm 42 which may be reciprocated to. reciprocate the sleeveswithin the cavities.

Partible neck molds 43, 44 are positioned formovement. into and out ofregister with v thetubular cavities.

As shown in Fig. 16 the'parts arein position for the beginning of thecycle with the tubular cavities having plastic material therein. Fig. 17shows the movement of the sleeves upwardly toz forceplastic material.into the neck molds. The cycle of operationswouldbe. con ducted in thesame manner as. in: the. operations shown in- Figs. 1 through 6vinclusive.

An important advantage of the; improved; methodof forming hollowplastic. articles is thatxthe tubular cavity is always filled withplastic material: andfthewentrapment of air is entirely eliminated,resulting in a more uniform plastic article.

the neck. mold, thereby forming. The sleeve. is. then rotated.

A further advantage is that the formation of the neck finish isaccomplished under controlled pressure supplied by the sleeve. Thispressure may be more uniformly and accurately controlled than it ispossible to obtain through any effort to control the pressure upon theplastic as generated by the parent extrusion device. In addition thiscontrolled pressure, because of its more direct and effectiveapplication; maybe; of a much lesserdegree of force than that whichisnormallysupplied by the parent extrusion device.=-.

The invention-shas been; described as a being, applied to organicplastic materials. The terms plastic and thermoplastic, as used "herein,define any .organic,material which has the requiredjcondition.ofiplasticity to permit expansion and setting in predetermined form.

The terms tubular-and tubing assused; herein, are intended to includeanyhollow shapes in which plastio material may be, ;fOI'I11,BdIL includingnon-circular T and it} regularshapes. Y

Modifications may be resorted to within thespirihand scope of theappended claims.

I claim:

1. The method of forming prelimin'ary blanks. of plastic moldingmaterialfor the production of 1 hollow plastic articles which comprises thesteps of providing a parent body of plastic material in workablecondition, segregating from. said parent body and in an repenend chambera--measured quantityof=- sueh molding material, applying pressure-toone-end of said segregated quantity: of material. to mold' a finishedportion -on and integral with theopposite. end of saidquantitysimultaneously re-- leasing said molding pressureupon-andendingthe-seg regation of said quantityof materialgsimultaneously injecting newmateria-lintoone end of said ch amber whileextruding material from the opposite end th ereofiuv the materialleaving said-chamber being in hollow tube form and integralwith said-previously molded finished? portion, segregating thesaidnewmaterial-in-the chamber" from said parent body of material, and severingthe ex truded tube formation from said new segregated material 2. Themethod off forming preliminary blanks of plastic molding-materialforthe-- production ofhollow plastic articleswhich comprisesthe steps-of. providing a parentmass ofplastic material in moldablecondition, simultaneously segregating-"from saidparent body andin anopen'end chamber ameasuredrqu antity ofsuch molding" material andapplying 1OCa'liZ'edf PI'B5SHTfi\tO one end of said segregatedquantityfof material to-mold a .iinis hed portion integral with theopposite end? thereof;- concurrently releasing said localized pressure;upon and ending;

ured quantityv of" such molding material: into an open.

ended chamber, molding a finished portion on and in tegral. with the.opposite end of said segregated quantity of workable plastic material,ending these'gregatiohof said quantity of material, extruding furthermaterial into one end of said chamber while extruding other materialfrom. the opposite end, of said chamb l' the material leaving saidchamber in hollow tube form and? beingintegral with: said moldedfinished portion, resegregating the material in the chamber from; saidparent body of material, and severingthe extruded tube formation withits said molded portion from said resegregated material.

4. The method of forming preliminary blanks of plastic molding materialfor the production of hollow plastic articles which comprises the stepsof molding a finished portion on and integral with an exposed end of asegregated quantity of workable plastic material, ending the segregationof said quantity of material, extruding further material into one end ofsaid chamber while extruding the segregated material from the oppositeend of said chamber, the material leaving said chamber in hollow tubeform and being integral with said molded finished portion, resegregatingthe material in the charnher from said parent body of material, severingthe extruded tube formation with its said molded portion from saidresegregated material, and repeating the several steps.

5. The method of forming preliminary blanks of plastic moldable materialfor the production of hollow plastic articles which comprises the stepsof providing a segregated measured quantity of workable plastic materialin an open end chamber, molding a hollow finished portion on andintegral with the material exposed by the said open end of said chamber,ending the segregation of said material, extruding further material fromthe parent body thereof into one end of said chamber while extruding thesegregated material from the open end of said chamber, the materialbeing extruded from said chamber being in a hollow form integral withand continuing the hollow formation. of said molded finished portion,resegregating the material in the chamber from said parent body,severing the extruded hollow tube formation from said resegregatedmaterial and repeating the several steps.

6. The method of forming preliminary blanks of plastic moldable materialfor the production of hollow plastic articles which comprises the stepsof providing a segregated measured quantity of workable plastic materialin an open end chamber, molding a hollow finished neck portion on andintegral with the material exposed by the said open end of said chamber,ending the segregation of said workable plastic material, extrudingfurther material from the parent body thereof into one end of saidchamber while extruding the segregated material from the open end ofsaid chamber, the material being extruded from said chamber being in ahollow tube form integral with and continuing the hollow formation ofsaid molded neck portion, resegregating the material in the chamber fromsaid parent body, severing the extruded hollow tube formation from saidresegregated material, and repeating the several steps.

.7. A method for forming plastic containers from heated plasticizedmaterial which includes the application of pressure from two separateand distinct sources of pressure, said method including the steps ofintroducing a measured amount of said material from a parent source intoa generally tubular cavity open at one end, segregating said measuredamount of material from the parent source thereof, molding a finishedportion on one end of said measured amount, and moving said moldedportion axially away from said tubular cavity while extruding throughsaid open end a hollow tubular formation integral with said moldedportion, said molding and said extrusions being obtained through theapplication of said separate pressures, respectively, in predeterminedorder.

8. A method for forming plastic containers from heated plasticizedmaterial and involving the application of a plurality of separatepressures, said method including the steps of first applying a firstextrusion pressure to a parent source of said material to therebyextrude a measured amount of the material into a generally tubularcavity, segregating said measured amount of material from said parentsource, applying a second injection pressure to injection mold afinished portion on one end of said measured amount, moving saidinjection molded portion axially away from said tubular cavity whileextruding a further portion of said measured material from said tubularcavity, said further extrusion being of hollow tubular formation andintegral with said molded portion, the extrusion of said further portionbeing obtained through the application to said material of a pressuredifierent from said injection pressure.

9. A method for forming hollow plastic containers from heatedplasticized material to which separate extrusion and molding pressuresderived from separate and distinct sources of pressure are applied, saidmethod including the steps of applying an extrusion pressure to a parentbody of said material to extrude a measured amount therefrom into agenerally tubular cavity open at one end, momentarily segregating thematerial in said cavity from said parent body thereof, applying amolding pressure to said segregated measured material to mold a finishedportion on one end thereof, ending the segregation of said material, andmoving said molded portion from said tubular cavity opening whileapplying pressure to said parent body to extrude therefrom a furthertubular formation integral with said molded portion.

10. In a method of making a plastic article from heated plasticizedmaterial filling a cavity communicating with an annular dischargeorifice, the steps of subjecting material in said cavity to an injectionmolding pressure from a first pressure source to eject material from thecavity into an injection mold communicating with the orifice andimmediately adjacent thereto, and thereafter simultaneously moving saidmold away from said orifice and applying to said material an extrusionpressure difierent from said injection molding pressure and from asecond source to thereby extrude a tubularextension through said orificeintegral with the material filling said injection mold.

11. In a method of forming hollow plastic containers from heatedplasticized material wherein there is utilized a plurality of pressuresderived from separate and distinct sources thereof, said pressures beingexerted on such material filling a cavity having an annular dischargeorifice, the steps of shaping a finished portion on said material atsaid discharge orifice by the exertion of a first of said pressures onsaid material, and thereafter moving said finished portion axially awayfrom said annular discharge orifice while extruding therethrough atubular plastic formation integral with said finished portion, theextrusion of said plastic formation being accomplished by the exertionof a second of said pressures different from said first pressure andderived from a separate pressure source.

12. In a method of forming hollow plastic containers from heatedplasticized material wherein there is utilized a plurality of separateand distinct means of pressurizing said plasticized material, the stepsof exerting pressure on the material to fill a cavity having an annulardischarge orifice, shaping a finished portion on said material at saiddischarge orifice by the exertion of a first pressure on said material,and subsequently moving said finished portion axially away from saidannular discharge orifice while extruding therethrough a tubular plasticformation integral with said finished portion, the extrusion of saidplastic formation being accomplished by the exertion of a secondpressure different from said first pressure.

References Cited in the file of this patent or the origlnal patentUNITED STATES PATENTS 2,262,612 Kopitke Nov. 11, 1941 2,288,454 HobsonJune 30, 1942 2,443,053 Parmelee June 8, 1948 2,562,523 Brunet July 31,1951

